(1) Field of the Invention
The present invention relates to an incoming call transfer controller and an incoming call transfer control method in a switching system which contains a telephone terminal capable of dealing with a plurality of lines (line numbers). The controller and the control method are provided for the purpose of performing control so as to transfer a call incoming to the telephone terminal which gives no response to the call to another telephone terminal.
(2) Description of the Related Art
In recent years, in a tele-marketing market or business receiving telephone calls including complaints from customers, and so on, there has been provided a function (switch box function for a multi-line operation) for enabling a receptionist (charge of reception) to respond to a call incoming to a multi-functional (line) telephone set and convey (transfer) the call to a person in charge according to the content of the call. This function can be realized by containing telephone sets (multi-line telephone sets) capable of dealing with a plurality of line numbers (telephone numbers) in various switching systems such as private branch exchanges and interfacing the switching systems with the multi-line telephone sets without using any special devices.
Accordingly, the multi-line telephone set is normally permitted to share the main line numbers of the other multi-functional telephone sets in addition to its own main line number (multi-line construction).
For example, referring to FIG. 32, there is shown a multi-line construction of multi-line telephone sets. If a switching system contains three multi-line telephone sets 100, 200 and 300 having prime line numbers (normally, the telephone numbers of telephone sets) X, Y and Z respectively as shown, the telephone set 100 can use the prime line numbers Y and Z of the other telephone sets 200 and 300 in addition to its own prime line number X. The telephone set 200 can use the prime line numbers X and Z of the other telephone sets 100 and 300 in addition to its own prime line number Y. Similarly, the telephone set 300 can use the prime line numbers X and Y of the other telephone sets 100 and 200 in addition to its own prime line number Z.
In other words, the telephone set 100 has slave telephone numbers Y and Z in addition to a master telephone number X. The telephone set 200 has slave telephone numbers X and Z in addition to a master telephone number Y. The telephone set 300 has slave telephone numbers X and Y in addition to a master telephone number Z.
In the telephone sets 100, 200 and 300 shown in FIG. 32, numerals 101, 201 and 301 respectively denote displaying units such as liquid crystal displays, numerals 102, 202 and 302 receivers respectively and numerals 10a, 10b and 10c display lamps respectively for informing users of calls incoming to corresponding telephone numbers or the ongoing use of line numbers (engaged in calling) by lighting or flushing on and off.
If a call comes into the user of the telephone set 100 (telephone number X) for example, since the telephone number X is shared by the other telephone sets 200 and 300, ring tones are made not only in the telephone set 100 but also in the telephone sets 200 and 300 simultaneously. At the same time, the display lamp 10a of each of the telephone sets 100, 200 and 300 corresponding to the telephone number X is caused to flush on and off and thereby the incoming call is notified to the users of each of the telephone sets 100, 200 and 300.
Thus, for example, even when the user of the telephone set 100 is absent, response can be made to a call which has come into the telephone set 100 (call incoming to the telephone number X) with the telephone set 200 (alternatively, the telephone set 300) by performing an off-hook operation by picking up the receiver 202 (alternatively, the receiver 302) of the telephone set 200 (or 300). The telephone set 100 can have telephone numbers Y and Z and use these numbers even if the telephone sets 200 and 300 do not exist. In this case, the telephone set 100 is permitted to use the three telephone numbers X, Y and Z exclusively for itself.
Referring to FIG. 33, there is shown in block an example of a multi-line operation system realized by using the above-described multi-line telephone set 100 (alternatively, the telephone set 200 or 300). The telephone set 100 shown is contained in a switching system 400 and connected through this switching system 400 to a public network 500. In this case, the telephone set 100 can handle totally three telephone numbers according to setting in the switching system 400 side. These telephone numbers are an outside line number "092-***-3211" (logical number of an incoming trunk 600) as a master telephone number X and outside line numbers "092-***-3212" (logical number of an incoming trunk 700) and "092-***-3213" (logical number of an incoming trunk 800) as slave telephone numbers Y and Z.
Thus, the telephone set 100 can be used for reception business including transferring of an incoming call to a specified person in charge according to the originator of this call, and so on. In other words, a person at the reception desk can identify the originator of a call incoming to the telephone set 100 by responding to the call and then transfer the call to a person in charge according to the caller.
For example, if the originator of a call incoming to the telephone number X ("092-***-3211") is a customer A (telephone set 501), the receptionist transfers the call to the telephone set 601 of a person in charge of the customer A of her own company (calls the telephone set 601). If the originator of a call incoming to the telephone number Y ("092-***-3212") is a customer B (telephone set 502), the receptionist transfers the call to the telephone set 602 of a person in charge of the customer B of her own company. If the originator of a call incoming to the telephone number Z ("092-***-3213") is a customer C (telephone set 503), the receptionist transfers the call to the telephone set 603 of a person in charge of the customer C of her own company. In reality, such transfer processing is executed by changing a called side included in data created for each call, which is called call control data, to a transfer destination with the switching system 400.
The above-described transfer operation is usually performed in a manner that the receptionist identifies the caller by responding to the incoming call and then dials the transfer destination by, for instance keeping the call on hold. In recent years, however, a request has been made for transferring an incoming call to a destination without actually responding to the call (non-response transfer).
Such a request has been made because if caller number notification services are rendered to the telephone sets 501 to 503 of the customers A, B and C by utilizing ISDN or the like, by displaying caller information including a telephone number, a caller's name, and so on, regarding the originator of a call which has come into the telephone set 100, on the displaying unit 101, the receptionist can identify the originator without actually responding to the call (without performing an off-hook operation).
Thus, in order to realize such non-response transfer, a call controller for performing transfer processing (incoming call transfer control method) like processing (1) or (2) described below has been provided in the switching system 400.
(1) An incoming call transfer destination is registered beforehand for each telephone set, in this case the telephone set 100 (for each prime line number X). When a call comes into the prime line number X of the free (no incoming call) telephone set 100, if no response is given to the call for over a certain period (alternatively, if a non-response transfer operation is performed by, for instance pressing a non-response transfer button), the call is then transferred to the destination which has been registered beforehand.
Processing performed by the call controller during such non-response transfer control will be described in detail below. It is assumed that as shown in FIG. 34, telephone sets 100' to 300' are contained in the switching system 400 in addition to the telephone sets 100 to 300, the telephone set 100' can use the prime line numbers B and C of the telephone sets 200' and 300' in addition to its own prime line number A, the telephone set 200' can use the prime line numbers A and C of the telephone sets 100' and 300' in addition to its own prime line number B and similarly the telephone set 300' can use the prime line numbers A and B of the telephone sets 100' and 200' in addition to its own prime line number C.
As shown in FIG. 35, the call controller registers the telephone set 100' (telephone set a) in a transfer destination registration table 401 in a main memory unit (not shown) beforehand as a transfer destination for an incoming call with respect to the telephone set 100 (logical number of a telephone set x).
In such a condition, for example, if a call for calling the prime line number X of the telephone set 100 comes in through the incoming trunk 600 (see FIG. 33), the call controller creates a terminal control table for dealing with line numbers of telephone sets (ETCM: Expanded Terminal Control Memory) 402 like that shown in FIG. 36, a terminal control table (TCM: Terminal Control Memory) 403 like that shown in FIG. 37 and call management information (CDB: Call Data Block) 404 like that shown in FIG. 38.
Specifically, the call controller registers the logical number of each of the telephone sets 100 to 300 which can handle the line number X (alternatively, Y or Z) in the terminal control table 402 for dealing with telephone set lines. The call controller also registers the logical numbers of each of the telephone sets 100' to 300' which can handle the line number A (alternatively, B or C) therein. The call management information 404 are registered in the terminal control table 403 for each of the logical numbers of the telephone sets 100 and 100' and the incoming trunk 600. The call management information 404 includes information indicating that a call origination (caller) is the incoming trunk 600 (logical number of the incoming trunk 600), information indicating that a call destination (receiver) is the telephone set 100 (logical number of the telephone set 100), information regarding the existence of a registered transfer destination, information regarding a calling state (during calling or during communication), and so on.
The call controller outputs a ring tone to the incoming trunk 600 (such that the caller can hear the ring tone) and calls the line number X (ring tones of all the telephone sets 100 to 300 which can use the line number X are sounded) based on the terminal control table 402. During this operation, the call controller sets timers for each call management information 404.
In such a condition, if the user of the telephone set 100 gives no response to the incoming call for a certain period, since the timer takes time out, the call controller then recognizes the existence of the registered transfer destination by referring to the call management information 404 (CDB #n) in which the time out has occurred. Then, the call controller recognizes that the transfer destination is the telephone set 100' by referring to the transfer destination registration table 401 based on the "receiver" (in other words, the logical number of the telephone set 100) registered in the call management information 404.
After the recognition of the transfer destination, for example as shown in FIG. 39, the call controller clears the information regarding the existence of the "registered transfer destination" included in the call management information 404, changes the information of the "receiver" to the information of the "logical number of the telephone set 100'" and stops calling the line number X, calls the telephone set 100' instead to execute the non-response transfer.
If the user of the telephone set 100 presses the non-response transfer button during calling the line number X, the logical number of the telephone set 100 and the pressing of the non-response transfer button are notified to the call controller. Accordingly, the call controller identifies the proper call management information 404 (CDB#n) by referring to the terminal control table 403 based on the notified logical number of the telephone set 100.
Then, the call controller recognizes that the transfer destination has been registered by referring to the call management information 404 (CDB#n) and refers to the transfer destination registration table 401 based on the "receiver" (in other words, the logical number of the telephone set 100) set in the call management information 404. Accordingly, the call controller recognizes the telephone set 100' as the transfer destination, stops calling the line number X and calls the telephone set 100' instead to execute non-response transfer.
(2) If there is a call incoming to the prime line number X of the free telephone set 100, by inputting transfer destination information by dialing or the like based on caller information displayed by the displaying unit 101 while the telephone set 100 is kept in an on-hook state, the call incoming to the prime line number X is transferred to the telephone set corresponding to the transfer destination information.
In this case, the call controller performs processing described below. Similarly to the procedure described above in (1), the call controller creates a terminal control table 402 (see FIG. 36) for dealing with telephone set lines, a terminal control table 403 (see FIG. 37) and call management information 404 (see FIG. 38). Then, the call controller outputs a ring tone to the incoming trunk 600 (such that the caller can hear the ring tone) and calls the line number X (ring tones of all the telephone sets 100 to 300 which can use the line number X are sounded) based on the terminal control table 402.
In such a condition, if a transfer destination telephone number is dialed by the telephone set 100 which is kept in an on-hook state, the logical number of the telephone set 100 and the dialed number are notified to the call controller. Then, the call controller identifies the corresponding call management information 404 by referring to the terminal control table 403 based on the notified logical number of the telephone set 100, stops calling the line number X by setting the logical number and the notified dialed number in a region for registering the "receiver" of the call management information 404 and calls the telephone set 100' instead to execute non-response transfer.
With the call controller (incoming call transfer controller), if there is a call incoming to the prime line number X of the free telephone set 100 from the customer A, the user can transfer the call to another telephone set 100' without responding to the call incoming to the prime line number X.
However, there are problems inherent in the incoming call transfer controller (control method) designed to execute the above-described processing (1) or (2). These control methods are effective when the telephone set of a transfer origin (transfer controller) controls only a single line number (prime line number X). But in the telephone set 100 which can handle a plurality of line numbers (X, Y and Z) as described above, it may occur that the plurality of line numbers simultaneously receive calls or are used. In such a case, the telephone set 100 cannot transfer calls incoming to the line numbers (slave telephone numbers) other than the prime line number (master telephone number) to the other telephone sets without any response.
More particularly, if a non-response transfer operation is performed (by pressing the non-response transfer button or dialing a transfer destination) by the telephone set 100 (alternatively, the telephone set 200 or 300) as described above, only the logical number of the telephone set 100 (200 or 300) which has performed the transfer operation is notified to the call controller. Since no information regarding the target line number of the transfer operation is notified, for instance even when the telephone set 200 of the prime line number Y executes non-response transfer for a call incoming to the line number X, the call controller must refer to the terminal control table 403 only based on the logical number of the telephone set 200. Consequently, the call controller cannot reach (recognize) the call management information 404 for managing the call (of the line number X) to be transferred.
In other words, in the non-response transfer operation performed by the telephone set 200, calls incoming to the prime line numbers X and Z of the other telephone sets 100 and 300 cannot be transferred. The same is true for the telephone sets 100 and 300 (alternatively, the telephone sets 100' to 300'). The telephone sets 100 and 300 (alternatively, 100' to 300') cannot perform non-transfer operation for calls incoming to the line numbers other than their own prime line numbers.
Thus, for instance even if she knows that calls incoming to the telephone set 100 are from the customers B and C, the receptionist cannot perform non-response transfer for each of the calls and must respond to at least one of the calls temporarily.
If the receptionist responds to the call incoming to the line number Y, the call which has come into the line number Y from the customer B is transferred to the telephone set 602 of a person in charge of the customer B. In the meantime, the call which has come into the line number Z from the customer C is kept waiting until the receptionist responds to the call incoming to the line number Z.
Also, if a call comes into the line number Z from the customer C while the receptionist is engaged in communication with the customer A by using the prime line number X, non-response transfer cannot be performed for the call incoming to the line number Z. Accordingly, the receptionist must cancel the communication performed by using the prime line number X or place the communication on hold and respond to the call incoming to the line number Z before transferring the call. Meanwhile, dealing with the call incoming to the main line number X from the customer A is discontinued or suspended.
As apparent from the foregoing, a problem inherent in the incoming call transfer controller (control method) is a great delay in dealing with calls incoming to the line numbers Y and Z other than the prime line number X. Such a delay occurs because if calls simultaneously come into the plurality of line numbers Y and Z other than the prime line number X of the telephone set 100, non-response transfer cannot be performed for any of these calls.
Another problem inherent in the incoming call transfer controller (control method) is not only a great delay in dealing with calls incoming to the line numbers other than the prime line number X but also a reduction in quality (service quality) of dealing with a party which has already been dealt with. This problem occurs because if new calls come into the line numbers Y and Z while the receptionist uses the prime line number X (e.g., during communication), the receptionist must place the communication with the opposite party performed by using the prime line number X on hold temporarily or discontinue the communication in order to deal with any of these incoming calls.